In the workplace, light reflectors and diffusers have evolved from a primitive metal reflector to various convoluted shapes of metal reflectors on one side of the light source and associated diffusers on the other. In factories and warehouses where illumination must be provided over a large area, a large number of incandescent fixtures have been used to provide standard levels of illumination. To reduce the total number of lamps needed, a variety of high intensity lamps using mercury, metal halide, high pressure sodium have been developed. In general, such high intensity luminaires are considerably more expensive than the comparable incandescent luminaires.